No power from 50 mls and up

Discussion in 'Street/strip 400/430/455' started by colonel, Aug 11, 2021.

  1. colonel

    colonel Speedjunky

    I finally got around routing a 3/8" fuel hose with a transparent fuel filter from the fuel hard line to the windshield and back to the fuel pump. The fuel filter was right in front of me when driving.

    Upon start up and idling, the pump filled the fuel filter (approx. 2" in dia and 4" long) about half up to the middle. I did a test run, cruising around town with a couple of kickdowns and finally to highway speed around 60-70 mls per hour. The symptoms came back from 50 mph and up.

    I noticed two things:

    #1 The stream of gas is not a continous one. Sometimes it´s a thick, hard stream, sometimes no fuel at all, sometimes a slow stream, sometimes "spitting". I did not notice a direct correlation between how the fuel was delivered and what position the gas pedal is at. Is this normal? I never gave thought to how EXACTLY the fuel is delivered to the carb and could imagine that engine vacuum and fuel level in the carb bowl play a role also, not only engine speed (i.e. revs, i.e. fuel pump lever movement).

    #2 At higher speed, the fuel level in the filter was VERY low, lower than the paper element. That was when the car started acting up. So apparently the engine pulls more gas than the pump can deliver (for some reason).

    Any ideas to the above?

    I do have to admit that the 3/8" fuel hose might have gotten a little squeezed between the hood and the rubber seal at the rear of the engine bay, but I don´t think this compromised the test run too much.
     
  2. rkammer

    rkammer Silver Level contributor

    Your testing still indicates a fuel delivery problem. You still need to take the tank down and inspect the fuel sock within the tank. Also, it hasn't been mentioned that there is a rubber section of fuel line that bridges the steel line located inside the frame rail under the driver's door. Check that for deterioration too.
     
    69GS430/TKX likes this.
  3. colonel

    colonel Speedjunky

    Yes, fuel delivering problem. I repeated the test drive with the gas cap off, no change.

    As my gas gauge doesn´t work (full to the right side) I wonder if I should replace the sending unit, once the tank is down? The unit has a good ground and if I ground the wire TO the sending unit, no movement of the needle either. At the same time, I know I have a dash electric problem (no dash illu, no left turn signal/hazard indicator light - right side ok), so not sure if it´s the unit or the wires/printed circuit.
     
  4. rkammer

    rkammer Silver Level contributor

    If you buy a new sending unit there will be a strainer sock included with it.
     
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  6. colonel

    colonel Speedjunky

    Yap, found those items already, on the fence to order, just not sure if a sock will be enough? RA does not carry them, just complete sending units.

    I checked on (read: grounded) the tan wire once more today, nothing! This actually should mean the culprit is in the front harness, not the sending unit. The pink wire in the fuse block has +12V, but I need to locate the body connectors to check for continuity on any of the tan wires.
     
    Last edited: Sep 14, 2021
  7. 69GS430/TKX

    69GS430/TKX Silver Level contributor

    Could it be a bad fuel pump? One other possibility: The steel fuel line has rusted through, somewhere where it contacts the frame, and the hole is facing up so there won't be any leaking gas on the ground that would indicate trouble. With air coming into the fuel line from that rusted hole, the engine might be starved at higher rpms.
     
  8. colonel

    colonel Speedjunky

    No, I replaced the fuel pump last week or the week before, was my initial thought also. I will check for punctuations of the fuel lines when I drop the tank.

    I ordered a new sending unit and will drop it in next week or the week after, as soon as I get to it.
     
    69GS430/TKX likes this.
  9. colonel

    colonel Speedjunky

    I believe I found the reason for what I guess is fuel starvation:

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    The tank is out, how do I remove the rust?
     
  10. Schurkey

    Schurkey Silver Level contributor

    Haul it to a local radiator-repair shop. Have them "boil" the tank.

    If it's horrible enough, they may have to coat the inside with sealant. My motorcycle tank is coated inside.

    'Bout the only alternative is to replace the tank.

    Either way, you need a new strainer sock. Perhaps the entire sending unit/pickup, depending on how rusted it is.
     
  11. knucklebusted

    knucklebusted Well-Known Member

    If there is no aluminum involved, you can use white vinegar. It will dissolve the rust in about 24 hours. Once that is done, do as suggested and get it coated afterwards. Too much moisture in the tank while it was sitting.
     
  12. colonel

    colonel Speedjunky

    After about a week of messing around with rust remover, the tank now looks like this:

    [​IMG]


    [​IMG]

    [​IMG]

    [​IMG]

    I couldn´t seem to be able to remove all rust from the baffle where the filler neck comes in, but it sure looks better than before.

    Hope to be able to get the new fuel sending unit and the tank back in by Saturday.
     
    DaWildcat likes this.
  13. telriv

    telriv Founders Club Member

    Do yourself a favor & replace that tank now. I'll almost guarantee you'll be replacing it in the future. The remaining rust will continue to advance & before you know it more than likely the same symptoms may/will occur again.

    Tom T.
     
    Last edited: Oct 14, 2021
    m louk, 1973gs and TORQUED455 like this.
  14. TORQUED455

    TORQUED455 Well-Known Member

    Exactly.

    Has anyone used gas tank sealer from Clark’s Corvair? That stuff was the bomb. I don’t even know if they make it anymore or if they’re still in business.
     
  15. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  16. TORQUED455

    TORQUED455 Well-Known Member

    Yes, but not the dented POR can one, the original. I see they say the POR is better, but the “Red-Kote” worked really well.
     
  17. colonel

    colonel Speedjunky


    Oh, I would have, if only I knew where to get one.

    RA, OPIG, CI, fleabay, the big river, Summit, tanksinc and other sources I found online, none of those carry tanks for the Electra. You get GS tanks, tanks for other GM cars like Impala, but nothing for the 72 Electra. Should anybody know a source, pls share.
     
  18. telriv

    telriv Founders Club Member

    I would guess we ALL missed it was a '72 Electra. Bad by ALL of us.
    Yes, "Red-Kote" is best.
    Clean the tank out better IF you can.

    Tom T.
     
  19. telriv

    telriv Founders Club Member

    ALSO, a member, 8587GN is parting a '71 Electra. Same tank??? Time to do a parts serach.
     
  20. colonel

    colonel Speedjunky

    Tank´s back in, together with a new sending unit (gauge was fully to the right). Car runs like crazy, 80 or 90 on a quick test drive, kickdowns ok, too. Gauge works now also.
     

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